Integrity Analysis of Multimedia File Transmission between Mobile Phones

Mobile forensics deals with evidence from mobile devices. Data recovered from the mobile devices are helpful in investigation to solve criminal cases. It is crucial to preserve the integrity of these data. According to research carried out [1], it has been noted that not all data extracted from mobile phones have discrepancies in hash values during integrity verification. It has been reported that only the Multimedia Messaging Service message type showed a variation in hash values when performing data extraction. The main objective in this work is to study the variance in the content of the graphic files transferred between mobile phones via Bluetooth or MMS. We also determine the causes of such variations, if any, while checking the graphics file integrity. Different parameters including distance and file format have been varied and a series of test were conducted using: mobile sets of same make same model, same make different model and different make different model on different graphic file formats of different sizes. Results obtained confirmed that there was no alteration of graphic files during Bluetooth transmission. However, while transmitting the graphic files through Multimedia Messaging Service, results showed notable alteration level for graphic files of certain file format and size.